Toilet paper is generally made in a form of a toilet roll in which continuous band-like paper is wound on a core called a paper core, and is available in the market as toilet roll products in which a plurality of these toilet rolls are packed.
In the toilet paper, users are interested in a price, a moisture-retaining property (wetness hand feel), flexibility (softness hand feel), and a surface lubrication property (smoothness hand feel), and request high-quality toilet paper in these respects.
Further, for a patient who suffers from a hemorrhoid disease or the like, it is difficult to rub the skin strongly with the paper in cleaning operation after excretion. For this reason, such a patient with a hemorrhoid disease is highly interested in toilet paper, which is improved in a wiping property, bulkiness, a moisture-retaining property, softness, and a surface lubrication property, so that he or she desires products satisfying these properties.
Further, the toilet paper is used not only after excretion, but also after urination for particularly a woman's cleaning operation. Here, since the woman's cleaning operation after urination is performed while the paper contacts a sensitive pubic region, there is a latent demand for toilet paper with a moisture-retaining property and softness.
Here, the toilet paper can be applied with chemicals which improve the characteristics such as a moisture-retaining property (wetness hand feel), flexibility (softness hand feel), and a surface lubrication property (smoothness hand feel).
However, the conventional toilet rolls applied with chemicals are expensive with low productivity. Further, the toilet roll is not sufficiently improved in all the characteristics and does not satisfy the user's demand.
For this reason, the conventional toilet roll products applied with chemicals have not been widely used.
Generally, in a conventional toilet roll, a paper roll manufactured by a paper manufacturing machine is conveyed to a winder and is rewound with the diameter of the toilet roll in the winder so as to manufacture a log having a width plural times or more a toilet roll width, and the log is cut into the toilet roll width so as to manufacture the toilet roll. In a case of manufacturing multi-ply products, continuous sheets reeled out from a plurality of paper rolls are multi-plied before the rewinding in the winder.
Then, a method for manufacturing the toilet roll applied with chemicals is disclosed in, for example, Patent Literatures 1 to 3 below.
In a technique of Patent Literature 1, steel-rubber embossing is performed when manufacturing a log from a paper roll set in a winder, chemicals are applied to embossing convex portions of a convex embossing roll, and the chemicals are transferred to a continuous sheet reeled out from the paper roll.
However, in the technique of Patent Literature 1, since the chemicals are applied only by the tips of the embossing convex portions to the continuous sheet, the amount of applied chemicals is small. Further, there is a concern that the chemicals may not be applied to an embossing concave surface. For this reason, it is difficult to sufficiently improve the surface lubrication property and the moisture-retaining property. Further, since chemicals applying process in which the paper strength is the lowest, and the embossing process, in which the continuous sheet are nipped with a predetermined pressure, are performed at the same time, paper breakage may be easily occurred and hence these processes need to be performed at a low speed. For this reason, it is difficult to improve the productivity.
Meanwhile, in a technique of Patent Literature 2, embossing is performed when manufacturing a log from a paper roll set in a winder and chemicals are applied in spraying.
However, even in the technique of Patent Literature 2, since the log is manufactured immediately after applying the chemicals, the chemicals tend to spread in the sheet after manufacturing the log, and hence there is a disadvantage that the log tends to loose the shape and deviate in winding due to stretching of the sheet caused by stretching of crepe. Particularly, since the log is cut, at a post stage, into a toilet roll, once the log deviates in winding or looses the shape, which causes defective toilet roll products, this means the yield is degraded, leading to low productivity.
Further, as in Patent Literature 1, since the log is manufactured immediately after the chemicals application applying process, the tension control is difficult, paper breakage may be easily occurred on forming perforation lines on the sheet and the tension of the continuous sheet is decreased, thereby the processing speed needs to be decreased. Accordingly, the productivity cannot be improved.
Further, in the technique of Patent Literature 2, since the chemicals are applied particularly by spray application after the embossing, the embossing may easily loose shape thereof. Furthermore, the amount of the ejected chemicals is limited because of the spraying in the winder, so, if the operation would not be performed at a low speed, the amount of applied chemicals to the continuous sheet would be insufficient, which leads inevitably to low productivity.
In a technique of Patent Literature 3, embossed crepe paper is obtained as base paper for toilet paper products. Here, continuous sheets are reeled out from a plurality of paper rolls; multi-ply forming is performed on continuous sheets, chemicals are applied to these multi-ply continuous sheets, water is further sprayed thereto so that the sheets become wet sheets, and embossing is performed on the sheets. Then, the respective multi-ply continuous sheets are separated before the rewinding.
However, in the technique of Patent Literature 3, since water is sprayed before the embossing, the embossing is performed before the continuous sheet is sufficiently impregnated with the chemicals or the water. For this reason, the chemicals, which are not impregnated yet into the surface of the continuous sheet, tend to adhere to a convex embossing roll and a receiving roll used for the embossing. Since this condition may cause the tearing of the sheet and stop of the manufacturing line for a cleaning operation, the productivity cannot be improved.
It is known that if oily chemicals are used for application, decrease of paper strength can be suppressed, and a toilet roll, which uses such oily chemicals, is also known. In such a toilet roll, the surface lubrication property can be sufficiently improved, but the moisture-retaining property is not sufficient. This is because, the oily chemicals are, among chemicals, known to unlikely to be impregnated into sheet layers. Further, for the toilet roll which uses oily chemicals, it is difficult to obtain the water disintegration property necessary for the toilet roll.